Telephone system



March 1943- I K. L. BURGENER 2,312,385

TELEPHONE SYSTEM Filed Oct. 24, 1941 2 sh 1 FF|CE RESIDENCE p suesnmou SUBSTATION B TRANSFFR CIRCUIT 5 v 124 l3liL iI LINE ['6' I I E f IGZ l l :l

m IZII H5150 LOG I33 CUTOFF R I00 I07 rawlee INVENTOR KARL 1.. suaezugn ATTORNEYS TELEPHONE SYSTEM Filed 001:. 24, 1941 2 Sheets-Sheet 2 RESIDENCE LINE cmcun' I7 26 GORD cmcurr eusmEss LINE cmcun 1s as I a 26C R2IO INVENTOR KARL L. BURGENER ATTORNEYS Patented Mar. 2, 1943 TELEPHONE SYSTEBI Karl L. Burgener, Chicago, 111., assignor to Associated Electric Laboratories, Inc, Chicago, 111.- a corporation of Delaware Application October 24, 1941, Serial No. 416,365

14 Claims.

The present invention relates to telephone systems and more particularly to improvements in call transfer arrangements of the character disclosed in Patent No. 2,095,712 granted October 12, 1937 to Edward S. Peterson. As explained in this patent, transfer service is especially useful to doctors, lawyers, and other professional men who are frequently absent from their offices and who do not wish to incur the expense of employing secretarial help for the purpose of answering telephone calls. It is also useful in the case of a doctor, for example, who desires to keep himself accessible to his patients at night when his office is unattended. In these and other cases, the subscribers concerned, by contracting for transfer service, are able to utilize their residence telephones for answering office calls and, accordingly, secure the equivalent of twenty-four-hour service in connection with their oflice telephone numbers.

It is an object of the present invention to provide an improved arrangement for giving transfer service of the characted described to any subscriber of a manual system.

According to a further object of the invention, the transfer facilities are so arranged that no special handling of the calls to be transferred is required on the part of the manual oflice operators.

According to another object of the invention, the transfer facilities may be selectively rendered active and inactive from the substation of the subscriber for whose use the service is provided.

In accordance with still another object of the invention, provisions are made for preventing a subscriber having the transfer service from rendering his transfer facilities inactive during an interval when a transferred call is in progress.

It is another object of the invention to provide call diverting facilities of the character described, which are simple in arrangement, require a minimum of equipment, and may be readily applied to any subscriber line of a manual system with only a few changes in the wiring of the line circuit terminating the line.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the specification taken in connection with the accompanying drawings in which Figs. 1 and 2, when laid side by side in the order named, illustrate a manual telephone system having incorporated therein improved transfer apparatus of the character briefly referred to above.

Referring now more particularly to the drawings, the system there illustrated comprises a manual office which is equipped with the sual operator switchboard and terminates the lines serving the subscribers of the adjacent area. Three subscribers lines, 11!, I1 and 12, which respectively serve the substations A, B and C, are illustrated as terminating at the operator switchboard in jacks 13, 14 and 15, respectively. The enumerated lines also terminate in the exchange in line circuits 16, 1'1 and 18, respectively, which are of identical arrangement. Thus the line circuit 16 is illustrated as comprising a line relay R210 and a cut-off relay R200, which are arranged to control a signal lamp 19 individual to the line 111. Similarly, the line circuit 11 individual to the line 1 1 comprises line and cut-off relays R230 and R221), respectively, which are arranged to control the signal lamp 211. The details of the line circuit 18 have notbeen shown, but it is noted that this line circuit also includes line and cut-off relays which are arranged to control the signal lamp 2|. For the purpose of setting up connections between the illustrated lines and the other lines of the system, a plurality of cord circuits are provided at the operator switchboard. These cord circuits are of identical arrangement and may be of any commercial type, each thereof being equipped with answer and call plugs which are respectively utilized in answering and extending calls. For example, the schematically illustrated cord circuit 25 is shown as comprising an answer plug 26 and a call plug 2'1.

For purposes of explanation, it may be assumed that the two substations A and B are the office and residence substations, respectively, of the same subscriber. It may further be assumed that this subscriber desires transfer service whereby calls intended for the oflice substation A are automatically diverted to the residence substation B during those hours when the office substation is unattended. To this end, a transfer circuit 30 is included in the line equipment terminating the line 10 in the manual oflice, and a key 35, of the Well-known locking type, is provided at the substation A for grounding the negative line conductor 10a of the line 10. In brief, the transfer circuit 311 comprises a pair of line relays R and R121], a cut-off relay R1011, a slow-to-operate transfer relay R130, and a pair of sleeve relays R and R which are individually associated with the lines 11 and 10, respectively. The manner in which this equipment is wired will be fully apparent from the following description of the operation of the transfer facilities. It is noted, however, that these facilities may be provided for the substation A by opening the jumper connections between the main distributing frame at which the conductors of the line I are terminated and the line multiple between the jacks individual to the line I0 at the operator switchboard, and connecting the transfer equipment therebetween.

In considering the operation of the system it may be assumed that the key 35 provided at the substation A is in the illustrated normal position and that the receiver of the handset provided at this substation is removed to make an outgoing call. transmitter and receiver of the handset are bridged across the conductors of the line I0 in the usual manner, to complete a circuit including the contacts I03 and I05 for energizing the two line relays RI I0 and RI20 in series. In operating, the relay RI I0 closes its contacts III to complete a circuit through the contacts I2I for energizing the transfer relay RI30. Concurrently with this operation, the line relay RI20 opens its contacts I2I to prevent the relay RI30 from remaining energized. Due to its slow-to-operate characteristic, the transfer relay RI30 does not operate in response to substantially concurrent operation of the two line relays. In operating, the relay RI 20 also closes its contacts I22 to complete a circuit including the resistor I23 and the contacts 20I and 202 for energizing the line relay R2I0. In operating, the relay R2I0 closes its contacts 2I I to complete an obvious circuit for energizing the lamp I9. The illuminated condition of this lamp serves to signal the operator in attendance at the operator switchboard in the manual office that a call has been extended to the jack I3, which should be disposed of.

To answer the call, the operator inserts the answer plug 20 of the cord circuit 25 in the jack I3,and in so doing connects negative battery potential through the sleeve contact 260 of this plug to the sleeve contact I30 of the jack I3, thereby to energize the sleeve relay RIBU. More specifically, the operating circuit for the relay RI60 extends from ground by way of the winding of this relay, the contacts I39 and I52 in parallel, the sleeve contacts I30 and 260 of'the jack I3 and the plug 26, respectively, and the winding of the sleeve relay in the cord circuit 25, to battery. When thus energized the relay RI60 operates and opens its contacts I6 I' to interrupt one branch of the circuit for energizing the sleeverelay RI50. At its contacts I02, the relay RI60 prepares a path for impressing negative battery potential upon the sleeve contact I40 ofthe jack I4 terminating the line II. At its contacts I63, the relay RI60 closes an obvious circuit for energizing the cut-off relay RI 00.

In operating, the relay RI00 closes its contacts IOI to prepare a locking circuit for the transfer relay RI30. At its contacts I02 and I04, the re- .lay RI00 connects the negative and positive conductors of the line I0 through the contacts I35 and I3! to the enga ed tip and ring contacts of the jack I3 and the answer plug 26. At its contacts I 03 and I05, the relay RI 00 disconnects the line relays RI I0 and RI20 from the conductors of the line I0; causing both of these relays to restore. In releasing, the relay RIIO opens its contacts III to interrupt the incomplete operating circuit for the transfer relay RI30. The relay RI 20, upon restoring, closes its contacts I2I to reprepare the operating circuit for the trans- In response to the latter operation, the.

fer relay RI30, and opens its contacts I22 to interrupt the path over which the resistor I23 is bridged across the tip and ring contacts of the jack I3.

In operating, the cut-01f relay RI00 also closes its contacts I06 to complete a circuit for energizing the cut-01f relay R200, this circuit extending from ground by Way of the winding of R200, the contacts MI and I06, and the resistor I01 to battery. In operating, the relay R200 opens its contacts 202 to disconnect the positive side of the line I0 from ground. At its contacts 20|,'the relay R200 opens another point in the operating circuit for the line relay R2I0. In releasing, the latter relay opens its contacts 2 to deenergize the signal lamp I9 in an obvious manner.

After the call has been answered by the operator in the manner just explained, and the desired directory number is transmitted to this operator from the calling party at the substation A, the call may be extended through the call plug 2'! to any desired substation of the system. For I example, the call plug 21 may be inserted in the jack I5 to establish a connection to the'line I2, after which the ringing key of the cord circuit may be operated to transmit ringing current over the line I2 for the purpose of energizing the ringer conventionally provided at the called substation C. When a connection is thus established to the line I2, the cut-off relay of the line circuit I8 operates to disconnect the windings of its associated line relay from the conductors of the line I2. When the call is answered at the called substation, the operator handling the call in the manual office may retire from the connection and rely upon the supervisory lamps forming apart of the cord circuit 25 to indicate the condition of the connection. When these lamps produce an indication that the connection has been released at the calling and called substations A and C, respectively, the operator may clear out the connection by withdrawing the answer plug 26 from the jack I3 and the call plug 21 from the jack I5. In response to the latter operation the line circuit I8 is restored to normal in the usual manner. When the answer plug 26 is Withdrawn from the jack I3, the sleeve contact I30 of this jack is disconnected from the negative terminal of the exchange battery to deenergize the sleeve relay RI60. In releasing, this relay opens its contacts I63 to deenergize the cut-01f relay RI 00. The latter relay, upon restoring, opens its contacts I05 to deenergize the cut-ofi relay R200 of the line circuit I6. Thus all of the equipment utilized in setting up the connection is restored to normal.

In considering the manner in which calls may be routed to the substation A at a time when the transfer circuit 30 is inactive, it may be assumed that a call originated at the substation C is extended to the operator headset through the cord circuit 25, and that the substation A is desired by the calling party. To complete the connection the operator handling the call inserts the call plug 27 in the jack I3 and, incident thereto, connects the sleeve contact I 30 of the jack I3 to the negative terminal of the exchange battery through the sleeve contact 210 of the plug 21, whereby the above-traced operating circuit for the sleeve relay RI60 is completed. In opcrating, the relay RI60 causes the sequential operation of the two relays RI00 and R200 in the manner previously explained, whereby the operating circuit for the line relay R2 I 0 is interrupted and the conductors of the line I0 are connected through the contacts I02, I04, I35 and I37 to the connected tip and ring contacts of thejack I3 and the plug 21. After these relay operations are completed, the operator may, by operating the ring key of the cord circuit 25, transmit ringing current over the line III for the purpose of energizing the ringer provided at the substation A. The manner in which a connection of this character is released will be clearly apparent from the above explanation.

The manner in which incoming and outgoing calls involving the residence substation B are handled by the operators in attendance at the switchboard in the manual office, is entirely conventional. In this regard it-will be noted that when either the answer plug 26 or the call plug 21 of the cord circuit 25, forexample, is inserted in the jack I4, the sleeve contact I40 of this jack is connected to the negative terminal of the exchange battery to complete a circuit through the parallel-connected contacts I3I and IBI for energizing the sleeve relay RI50. In the event the line I is occupied with a call at the time a call is routed from or extended to the line II, the sleeve relay R160 is operated so that the circuit for energizing the sleeve relay RI50 only extends through the contacts I3I. Regardless of this fact, however, the sleeve relay RI 50 operates and closes its contacts I5I to prepare a path for connecting the sleeve contact I30 of the jack IE to the negative terminal of the exchange battery. At its contacts I52, the relay RI50 opens one of the parallel branches of the above-traced operating circuit for the sleeve relay RI60. It will be noted, however, that this operation does not interrupt the operating circuit for the sleeve relay RIBI! so long as the transfer relay RI30 occupies its restored position. At its contacts I53, the relay RI50 completes a circuit including the resistor I54 for energizing the cut-off relay R220. In operating, the relay R220 opens its contacts 22I and 222 to interrupt two points in the operating circuit for the line relay R230. In case the call in progress is an outgoing call originated at the substation B, the line relay R230 is deenergized and opens its contacts 23I to deenergize the signal lamp 20, incident to the operation of the cut-off relay R220. On the other hand, if the call in progress is incoming to the substation B, the operation of the relay R220 prevents the subsequent operation of the line relay R230 when the call is answered at the substation B. Obviously the operated sleeve and cut-oil relays RIEil and R220 are deenergized and restore When the plug of the cord circuit 25, utilized in handling the connection, is withdrawn from the jack I4 to disconnect the sleeve contact I4c thereof from the negative terminal of the exchange battery.

In considering the manner in which calls are diverted to the substation B at .a time when the office substation A is unattended, it may be assumed that the subscriber at the latter substation actuates the key 35 to its off-normal position wherein the line conductor Ilia is connected to ground. Incident to this operation a circuit including the contacts I03 and the negative line conductor Ifla is completed for energizing the line relay RI I0. This relay remains in its operated position until the key 35 is manually restored to normal. It will be noted that if an outgoing call is originated at the office substation A, with the key 35 in its ofi-normal position, the line relay RI20 is short-circuited over a path which includes the contacts of this key, the bridging path between the conductors of the line It, the positive .side of this line, and the contacts I05. Accordingly, with the key 35 operated, calls cannot be extended from the substation A.

Upon operating in response to the operation of the key 35 to its oil-normal position, the line relay RI I0 closes its contacts II I to complete the above-mentioned circuit through the contacts I2I for energizing the slow-to-operate transfer relay R I 30. In operating, the relay RI 350 closes its contacts I33 to prepare the above-mentioned locking circuit for itself. At its contacts I3I and. I39, the relay RI opens the above-described branches of the respective operating circuits for the two sleeve relays RI50 and RI60. By virtue of this operation, only one of the two sleeve relays can subsequently be operated at any given time. At its contacts I32 and I38, the relay RI30 prepares the above-mentioned paths for impressing negative battery potential upon the sleeve contacts I30 and H30 of the jacks I3 and I4, respectively. At its contacts I4I, the relay RI30 opens a point in the previously traced operating circuit for the cut-off relay R200 of the line circuit I6. At its contacts I40, the relay RIBS prepares an alternative circuit for energizing the cut-off relay R220 of the line circuit ll. At its contacts I and I31, the relay RI 30 opens the paths over which the tip and ring contacts of the jack I3, individual to the line I0, may be connected to the conductors of this line. At its contacts I34 and I36, the relay RISI] connects the tip and ring contacts of the jack I3 to the conductors of the line II and the tip and ring contacts of the jack I4.

Following the operations just described, the transfer circuit 30 is actively conditioned to automatically divert to the substation B calls which are extended to the line l0 through the cord circuit 25, for example, and the jack I3 individual to the line I0. Thus, if the call plug 2'! of the cord circuit 25, for example, is inserted in the jack I3 during an interval when the transfer relay RISE! is operated, the tip and ring conductors of the cord circuit are connected through the tip and ring contacts of the jack I3 and the contacts I34 and I35 to the negative and positive conductors of the line II. Moreover, negative battery potential is impressed upon the sleeve contact I30 of the jack l3 to energize the sleeve relay RISIJ in a circuit which now only includes the contacts I52. In operating, the relay RIBII closes its contacts N33 to energize the cut-ofi relay RI00. At its contacts IISI, the relay RI60 opens the only branch of the circuit over which the sleeve relay RI 50 may be energized. At its contacts I 02, the relay RISE connects the sleeve contact I of the jack I4 to the negative terminal of the exchange battery through the contacts I32 and the resistor I24. The completion of this path serves to provide an indication that the line I I is busy. Thus if another operator should attempt to insert a call plug into the jack I4, the negative battery potential encountered on the sleeve contact I40 by the sleeve contact of the call plug in use, causes the supervisory equipment of the cord circuit in use to produce an indication that the line II is busy. Thus the operator handling the second call is prevented from intruding on the diverted call.

In this case the cut-oil relay RIIII], upon operating, closes its contacts I00 to complete the above-mentioned alternative operating circuit for the cut-off relay R220, this circuit extending from ground by way of the winding of R220, the contacts I40 and I05, and the resistor I01 to battery. In operating, the relay R220 performs the functions described above. At its contacts IOI, the relay RI completes the above-mentioned locking circuit for the transfer relay RI30. At its contacts I03, the relay RI00 opens the circuit over which the line relay RI I0 is being held energized. The relay RIIO now restores and opens its contacts III to interrupt the operating circuit for the transfer relay RI30.

From the above explanation it will be noted that the cut-off relay RI 00 performs the function of preventing the transfer circuit 30 from being rendered inactive under the control of the subscriber at the substation A during a period when the line II is occupied with a call which has been diverted thereto from the line I 0. In this regard it will be understood that the cut-off relay RI00 is held in its operated position for the duration of the call under consideration. With this relay operated, the transfer relay RI 30 is locked up through the contacts I33 and IOI. Further, the operating circuit for the line relay RI I0 is held open at the contacts I03 so that a subscriber at the office substation A can exercise no control thereover. The purpose of this arrangement is to prevent a call which has been diverted to the line II from the line I 0 from being interrupted before it is terminated in the normal manner.

After the diverted call has been extended to the line II in the manner just explained, and the relays RI60, RI00 and R220 have operated, the operator handling the call may actuate the ring key of the cord circuit 25 to project ringing current through the contacts I34 and I36 and over the line II to energize the ringer provided at the residence substation B. It will be apparent that when the call is answered a talking circuit is set up between the cord' circuit 25 and the substation equipment at the residence substation which includes the conductors of the line II, the contacts I34 and I36 of the transfer relayRI30, and the engaged tip and ring contacts of the jack I3 and the call plug 27.

When the supervisory equipment of the cord circuit 25 indicates to the operator handling the call that the connection has been released at both the calling and called substations, the operator may clear out the connection by withdrawing the answer plug 26 from the jack terminating the calling line and the call plug 2'! from the jack I3. Incident to the latter operation the sleeve contact I3c is disconnected from the negative terminal of the exchange battery to deenergize the sleeve relay RI30. This relay, in restoring, causes the sequential release of the two cut-off relays RI00 and R220 in an obvious manner. The relay RI00, upon restoring, first closes its contacts I03 to again energize the line relay RI I0, and then opens its contacts I 0I to interrupt the locking circguit for the transfer relay RI30. In operating, the relay RI I0 recloses its contacts I II to again complete the operating circuit for the transfer relay. Thus the transfer relay RI30 is prevented from restoring in response to the release of the cut-off relay RI00, assuming that the transfer key 35 has not been operated to its normal position during the period of the diverted call. Following the release of the relays RI50, RI00 and R220 and the reoperation of the line relay RI I0, the transfer equipment is restored to its normal active setting.

If a connection is set up through the cord circuit 25 between the line II and another line of the system at a time when the transfer circuit 30 is conditioned for operation the sleeve relay RI 50 is energized from the cord circuit when the call or answer plug of the cord circuit is inserted in the jack I4. In operating, the relay RI50 closes its contacts I53 to complete the previously traced operating circuit for the cut-off relay R220, and opens its contacts I52 to interrupt the only branch of the circuit over which the sleeve relay RII50 may be energized. Thus the relay RIBU is rendered non-responsive to the insertion of a call or answer plug in the jack I3. At its contacts I5I, the relay RI50 completes the previously mentioned path for impressing negative battery potential upon the sleeve contact I30 of the jack I3, this path extending from the negative terminal of the exchange battery by way of the resistor I 24 and the contacts I32, I38 and I5I. The purpose of completing this path is to provide an indication that the line associated with the jack I3 is occupied with a call.- Thus, if another operator inserts a call plug in this jack at a time when the sleeve relay RI50 and the transfer relay RI30 are operated, the supervisory equipment of the cord circuit in use functions to provide an indication that the line connected to the jack I3 is busy. When the connection involving the line I I is cleared out at the operator switchboard, negative battery potential is removed from the sleeve contact lie of the jack I4 to cause the sequential release of the sleeve relay RI50 and the cut-off relay R220. Thus the transfer circuit 30 is restored to its normal active setting.

From the above explanation it will be understood that the transfer circuit may be restored to its inactive setting under the control of. the subscriber at the office substation A at any time except when a call diverted from the jack I3 to the line II is in progress. Thus it will be noted that the operation of the sleeve relay RI50 which occurs incident to the setting up of a connection through the jack I4 to the line I I, does not cause the operation of the cut-off relay RI00. So long as this cut-off relay occupies its restored position the transfer circuit 30 may be released. To this end the transfer key 35 is restored to its normal position to deenergize the line relay RIIO. In releasing, the relay RIIO opens its contacts I II to deenergize the transfer relay RI30. Following the release of the latter relay, the transfer circuit is rendered inactive to divert calls from the jack I3 to the line I I. It will be noted that after the transfer relay RI30 is released by restoring the transfer key 35 to normal, an outgoing call may immediately be initiated at the ofiice substation A without in any way interfering with a connection which mat exist between the line I I and another line of the system over a route which includes the jack I 4.

While one embodiment of the invention has been disclosed, it will be understood that various modifications may be made therein which are within the true spirit and scope of the invention.

What is claimed is:

1. In a telephone system which includes a manual ofiice, an office line, a residence line, office and residence substations respectively served by said ofiice and residence lines, jacks terminating said lines in said oflice, means including an operator cord circuit for setting up connections between said lines and the other lines of the system, and means in said manual office selectively controllable over one of said lines from the substation served by said one line for diverting to the other of said lines calls which have been extended to said one line through said cord circuit and the jack terminating said one line.

2. In a telephone system which includes a manual office, first and second substation lines, jacks and line circuits terminating said lines in said manual ofiice, means including an operator cord circuit for setting up connections between said lines and the other lines of the system, means at the substation served by the first of said lines adapted for sustained operation to indicate that said substation is unattended, and means in the line circuit terminating said first line and controlled by the operation of said lastnamed means for automatically diverting to said second line calls which have been extended to said first line through said cord circuit and the jack terminating said first line.

3. In a telephone system including an operator switchboard, a pair of substation lines, jacks terminating said lines at said switchboard, means including an operator cord circuit for setting up connections between said lines and the other lines of the system, means for automatically diverting to a first of said substation lines calls which have been extended to the second of said substation lines through said cord circuit and the jack terminating said second line, means for rendering said call diverting means inactive, and means for preventing said last-named means from rendering said call diverting means inactive at a time when said first line is occupied with an incoming call which has been diverted thereto from said second line.

4. In a telephone system including an operator switchboard, a pair of substation lines, jacks terminating said lines at said switchboard, means including an operator cord circuit for setting up connections between said lines and the other lines of the system, means for automatically diverting to a first of said substation lines calls which have been extended to the second of said substation lines through said cord circuit and the jack terminating said second' line, means for rendering said call diverting means inactive, and means controlled from said cord circuit through the jack terminating said second line for preventing said last-named means from rendering said call diverting means inactive at a time when said first line is occupied with a call which has been diverted thereto from said second line.

5. In a telephone system which includes a manual office, an office line, a residence line, office and residence substations respectively served by said office and residence lines, jacks terminating said lines in said manual oifice, means including an operator cord circuit for setting up connections between said lines and the other lines of the system, means for automatically diverting to one of said lines calls which have been extended to the other of said lines through said cord circuit and the jack terminating said other line, means controllable from the substation served by said other line for rendering said call diverting means inactive, and means for preventing said last-named means from rendering said call diverting means inactive at a time when said one line is occupied with an incoming call which has been diverted thereto from said other line.

6. In a telephone system which includes a manual ofiice, an ofiice line, a residence line, ofiice and residence substations respectively served by said ofiioe and residence lines, jacks terminating said lines in said manual ofiice, means including an operator cord circuit for setting up connections between said lines and the other lines of the system, means for automatically diverting to said residence line calls which have been extended to said office line through said cord circuit and the jack terminating saidoffice line, means controllable from said ofii'ce substation over one side of said ofiice line for rendering said call diverting means inactive, and means for preventing said last-named means from rendering said call diverting means inactive at a time when said residence line is occupied with an incoming call which has been diverted thereto from said officeline.

7; In a telephone system which includes a manual office, an ofiice line, a residence line, offi'ce and residence substations respectively served by said ofiice and residence lines, jacks terminating said lines in said manual oflice, means'including an operator cord circuit for setting up connections between said lines and the other lines of the system, means for automatically diverting to said residence line calls which have been extended to said office line through said cord circuit and the jack terminating saidiofiice line, means controllable from said ofiice substation over one side of said office line for rendering said call diverting means inactive, and means controlled from said cord circuit through the jack terminating said ofiice line for preventing said last-named means from rendering said call diverting means inactive at a time when said residence line is occupied with an incoming call which has been diverted thereto from said office line.

8. In a telephone system, a substation line, a transfer relay for diverting calls intended for said line to another line of the system, two line relays normally bridged across said substation line, one of said relays being operativeiin response to the grounding of said substation line at the-"station served by said substation line and. both of said relays being operative in: response: to the bridging of said substation line at said station, a circuit for said A transfer'relayjointly controlled by said line re- 1ays, and"means responsive to a' call incoming to said'substationi line at'a time when said transfer relay is operated for disconnecting said line relays from said substation'line,

9. In a telephon'e'sy'st'em' a substation line, a transfer relay for diverting calls intended for saidline to another line of the system, two line relays normally bridged across said substation line, one of said relays being operative in response to the grounding of said substation line at the station served by said substation line and both of said relays being operative in response to the bridging of said substation line at said station, a circuit for said transfer relay jointly controlled by said line relays, means responsive to a call incoming to said substation line at a time when said transfer relay is operated for disconnecting said line relays from said substation line, and means operative when said other line is occupied with an outgoing call or a call routed directly thereto for preventing the operation of said last-named means and for providing an indication that said substation line is busy.

10. In a telephone system which includes an operator switchboard, a pair of substation lines, jacks terminating said substation lines at said switchboard and each including a control contact, means including an operator cord circuit for setting up connections between said lines and the other lines of the system, means for automatically diverting to one of said lines calls which have been extended to the other of said lines through said cord circuit and the jack terminating said other line, means controllable over said other line for selectively rendering said call diverting means active and inactive, a relay controlled over the control contact of the jack terminating said other line and operative each time a call is extended to said other line through said cord circuit, and means responsive to the operation of said relay 'for rendering said last named means non-controllable over said other line.

11. In a telephone system which includes an operator switchboard, a pair of substation lines, jacks terminating said substation lines at said switchboard and each including a control contact, means including an operator cord circuit for setting up connections between said lines and the other lines of the system, means for automatically diverting to one of said lines calls which have been extended to the other of said lines through said cord circuit and the jack terminating said other line, means controllable over said other line for selectively rendering said call diverting means active and inactive, a relay controlled over the control contact of the jack terminating said other line and operative each time a call is extended to said other line through said cord circuit, and means responsive to the operation of said relay with said call diverting means active for rendering said last-named means noncontrollable over said other line and for providing an indication that said one line is busy.

12. In a telephone system which includes an operator switchboard, a pair of substation lines, jacks terminating said substation lines at said switchboard and each including a control contact, means including an operator cord circuit for setting up connections between said lines and the other lines of the system, means for automatically diverting to one of said lines calls which have been extended to the other of said lines through said cord circuit and the jack terminating said other line, means controllable over said other line for selectively rendering said call diverting means active and inactive, a relay controlled over the control contact of the jack terminating said other line and operative each time a call is extended to said other, line through said,

cord circuit, means responsive to the operation of said relay for rendering said last-named means non-controllable over said other line, a

second relay controlled over the control contact of the jack terminating said one line and operative each time said one line is occupied with a call extended through the jack terminating said one line, and means responsive to the operation of said second relay for preventing the operation of said first-named relay.

13. In a telephone system which includes an operator switchboard, a pair of substation lines, jacks terminating said substation lines at said switchboard and each including a sleeve contact, sleeve relays individually controlled over said sleeve contacts and each operative each time a connection is extended through the associated jack, means including an operator cord circuit for setting up connections between said lines and the other lines of the system, means for automatically diverting to one of said lines calls which have been extended to the other of said lines through said cord circuit and the jack terminating said other line, means for selectively rendering said call diverting means active and inactive, and means responsive to the operation of either of said sleeve relays at a time when said call diverting means is active for providing an indication that the non-associated line is busy.

14. In a telephone system which includes an operator switchboard, a pair of substation lines, jacks terminating said substation lines at said switchboard and each including a sleeve contact, sleeve relays individually controlled over said sleeve contacts and each operative each time a connection is extended through the associated jack, means including an operator cord circuit for setting up connections between said lines and the other lines of the system, means for automatically divertingto one of said lines calls which have been extended to the other of said lines through said cord circuit and the jack terminating said other line, means controllable over said other line for selectively rendering said call diverting means active and inactive, means responsive to the operation of'the sleeve relay individual to said other line at a time when said call diverting means is active for rendering said last-named means non-controllable over 'said other line, and means responsive to the operation of either of said sleeve relays at a time when said call diverting means is active for providing an indicationthat the non-associated line is busy. 7

KARL L. BURGENER. 

